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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
  
</head>
<style>
  * {
    padding: 0;
    margin: 0;
  }
  body{
    position: relative;
  }
  main{
    width: 900px;
    height: 500px;
    border: 1px solid red;
    margin: 120px auto;
    overflow: auto;
    position: relative;
    
  }
  div{
    width: 100%;
    height: 200px;
    /* margin: 30px; */
    border: 1px solid red;
    position: absolute;
    left: 50%;
  }
</style>
<body>
    <main>
        <div>4444444444444444444</div>
    </main>
</body>
<script>
    

    
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</html>
